| 摘要 |
<p>The projection lens is for the picture screen of a cathode-ray tube, being in three groups. The first group from the picture end (G1) has a component with a small relative optical power, and is basically for correction of stop-dependent aberrations. The second group (G2) has a biconvex components (L2) of positive power, supplying the entire positive power of the whole lens. The third one has a negative component and acts as a scanning field curve eliminator (G3) correcting the Petzval Curve of the first and second groups. The optical powers of the three groups (K1, K2, K3) are defined by the inequalities 0.4> k1 > 0.1, 1.1>K2> 0.85 and -1.9> K3> -1.0.</p> |
